JPS645247B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a pyroelectric infrared detection element using a pyroelectric material.

Conventional configuration and problems Pyroelectric infrared detectors are sensors that detect temperature changes, so they produce output when a chopper is used, when the sensor is panned, or when the object to be measured moves. Therefore, when used as a security sensor, a segmented spherical mirror 2 is used, as shown in FIG. 1, which causes spatial chopping when a human being (object to be measured 7) moves. This mirror 2 collects infrared rays 6 from the object to be measured 7 onto the pyroelectric infrared detector 1 . When the object to be measured 7 moves, the incident infrared light 6 moves to an adjacent segment mirror, causing spatial chopping.

In this case, in order to create a combination of the detector 1 and the mirror 2, it is necessary to align the two, and the security sensor also becomes large. In addition, it is not suitable for detecting finer moving objects.

OBJECTS OF THE INVENTION An object of the present invention is to provide an infrared detection element that has a simple structure, is compact, and can easily detect small moving objects.

Structure of the Invention The present invention provides a support body having an inclined through hole, on the wide opening side of the through hole, the width of which is narrower than that of the wide opening;
A first pyroelectric element longer than the wide aperture length is provided in a bridge shape, and a second pyroelectric element is provided on the narrow aperture side of the support so as to almost cover this narrow aperture, and the second pyroelectric element is provided on the narrow aperture side of the support. This allows more infrared light to enter.

DESCRIPTION OF EMBODIMENTS One embodiment of the present invention will be described in detail below. Second
The figure is a sectional view showing an embodiment of the infrared detecting element according to the present invention, and FIG. 3 is a plan view thereof.

A pyroelectric element 4 is mounted on the open end side of a support base 5 having an inclined through hole 8 with its light receiving surface facing the support body 5 side. Further, a pyroelectric element 3 having light-receiving electrodes formed on both surfaces is attached to the wide opening side of the support 5 by gluing both ends of the element 3 to the support 5 like a bridge. The pyroelectric element 3 is formed so that its width is narrower than the width of the opening on the wide side of the hole 8, and its length is longer than the opening length. Lead wires (not shown) connect each pyroelectric element 3, 4.
It can be taken out directly or through the support stand 5. The inclined inner surface of the support base 5 is coated with an infrared reflective material 9. If the incident infrared rays 6 are parallel, the infrared rays incident from areas A and E will be incident on the back surface of the pyroelectric element 3, and the infrared rays incident from area C will be incident on the surface of the pyroelectric element 3. Further, infrared rays incident from areas B and D are incident on the pyroelectric element 4. By moving the incident infrared light 6 to areas A, B, C, D, and E in this way, the pyroelectric element 3 (back side),
The light-receiving elements change from 4, 3 (front) to 4, 3 (back), which means that they are spatially chopping when viewed from the element side. As described above, according to the configuration of the present invention, an infrared detection element capable of spatially dividing into zones can be manufactured using a pair of pyroelectric elements. Next, specific examples will be shown.

An oxide film is formed on a silicon wafer by thermal oxidation or CVD, and the central part of the oxide film is removed by photoetching for patterning. When anisotropic etching is performed using this oxide film as a mask using an ethylenediamine-procatechol etching solution, a through hole having an inclination in the center is formed. After drilling and etching are completed, the outside is cut to the required dimensions to form the support stand 5. An infrared absorbing material such as NiCr is deposited on the pyroelectric elements 3 and 4 as electrodes.
The pyroelectric elements 3 and 4 are cut to a specified size and fixed to a support base 5 with adhesive. There is an optimal design for each dimension at this time, but to summarize, the thickness of the Si support is approximately 400μ, the opening is approximately 1mm x 1.5mm, and the opening is approximately 0.45mm x 0.95mm. , assuming that the pyroelectric element 3 is approximately 0.25 mm x 2.0 mm and the pyroelectric element 4 is approximately 1 mm x 1.5 mm, the division width of each zone A to E is 0.2 to 0.25 mm.
It becomes the rank. Therefore, fairly fine division is possible, and it is also possible to inspect fine-line thermal patterns. Furthermore, if a lens system or the like is used, it becomes possible to use the device with a larger field of view.

Effects of the Invention As described above, the present invention provides a bridge-shaped first pyroelectric element that is narrower than the wide opening width and longer than the wide opening length, on the wide opening side of the through hole of a support body having an inclined through hole. On the other hand, a second pyroelectric element is provided on the narrow aperture side so as to almost cover this narrow aperture, and infrared light is incident from the first pyroelectric element, and the detection element itself is It has a field-of-view zone division function, has a compact and simple configuration, and enables finer spatial division, making it possible to detect small moving objects. In this case, if the thickness of the support base is increased, the optimal division width will be increased, so an optimal design can be made as necessary.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of a conventional infrared detector using spatial zone division, FIG. 2 is a sectional view showing an embodiment of an infrared detecting element according to the present invention, and FIG. 3 is a plan view thereof. DESCRIPTION OF SYMBOLS 1... Pyroelectric infrared detector, 2... Segmented spherical mirror, 3, 4... Pyroelectric element, 5... Support stand, 6... Incident infrared light, 7... Object to be measured, 8...
...Through hole, 9...Infrared reflective material.

Claims (1)

[Scope of Claims] 1. An infrared reflective surface is formed on the inner surface of the through hole of a support base having an inclined through hole, and an infrared reflecting surface is formed on the support base surface on the wide opening side of the through hole, and an infrared reflective surface is formed on the support base surface on the wide opening side of the through hole. A double-sided photosensitive first pyroelectric element that is narrow and longer than the aperture length of the wide aperture is provided in a bridge shape spanning the length direction of the wide aperture, so as to substantially cover the narrow aperture on the narrow aperture side of the through hole. An infrared detection element characterized in that a second pyroelectric element is provided in the pyroelectric element. 2. The infrared detecting element according to claim 1, wherein the support is made of a silicon wafer, and the through holes are formed by anisotropic etching.